Directories with "Copy 2" in their title are independently scanned second copies, added to increase your likelihood of finding matches despite OCR errors. Some types of OCR errors might occur for only one copy, so, by having two copies, you might find a match that you otherwise would not. This is especially true for OCR errors related to the physical way a directory is scanned, the scanner's hardware of software settings, or damage to a directory. In practice, you will often see identical results in both copies, but sometimes you will find matches in one that aren't shown in the other.